1. Field of the Invention
The present invention relates to a 1-azoniabicyclo[3.3.0]oct-1(5)-ene salt derivatives and a process for the preparation of the same. The derivative is useful as an intermediate for synthesizing various medicines and agricultural chemicals.
2. Related Arts
According to a conventional method, 1-azoniabicyclo[3.3.0]oct-1(5)-ene salt derivatives shall be prepared by reacting .gamma.-butyrolactone with potassium cyanate, heating the resulting .gamma.-(N-2-pyrrolidinonyl) butyric acid in the presence of soda lime, and then reacting the resulting 1-azabicyclo[3.3.0]-4-octene with perchloric acid [Miyano et al "Synthesis", page 701 (1978)]. As a method for preparing the intermediate of .gamma.-(N-2-pyrrolidinonyl) butyric acid, such a method has also been proposed that 2-pyrrolidone is reacted with metallic sodium and then reacted with .gamma.-butyrolactone [Miyano et al "J. Heterocyclic Chem.", Vol. 19, page 1465 (1982)].
The conventional processes given above shall be shown, as follows. ##STR1##
The conventional processes have following disadvantages. Namely, the first step for reacting .gamma.-butyrolactone with potassium cyanate to synthesize .gamma.-(N-2-pyrrolidinonyl) butyric acid requires high reaction temperature (about 200.degree. C.) and provides a low yield (about 40%). While, the method of reacting 2-pyrrolidone with metallic sodium and then reacting with .gamma.-butyrolactone may cause an abnormal reaction of accidental explosion.
The second step of the conventional process, namely for heating .gamma.-(N-2-pyrrolidinonyl) butyric acid in the presence of soda lime to synthesize 1-azabicyclo[3.3.0]-4-octene has also disadvantages of that high reaction temperature (250.degree.-300.degree. C.) is require, and that the reaction product has a low stability.